Abstract: Polymer nanocomposites are produced using a supercritical fluid (e.g., supercritical carbon dioxide). The carbon dioxide mixes with the nano-clay particulates and diffuses into the galleries to make the particulates susceptible to separation. The particulates can be subjected to a mechanical beating operation to reduce them in size and to reduce the formation of agglomerates. The particulates and supercritical fluid are then injected as a mixture directly into a polymer stream. Because the line leading to the polymer stream is open, the pressure drop as the particles travel to the polymer causes the particles to exfoliate. Further, because the supercritical carbon dioxide is present with the particles during exfoliation and injection into the polymer, the particles tend to stay exfoliated and disperse as fine particles throughout the polymer. The supercritical carbon dioxide also lowers the viscosity of the polymer to assist in distributing the exfoliated particles.

Abstract: A low cost method of fabricating bipolar plates for use in fuel cells utilizes a wet lay process for combining graphite particles, thermoplastic fibers, and reinforcing fibers to produce a plurality of formable sheets. The formable sheets are sandwiched between outer layers consisting of polymer and graphite particles, then molded into a bipolar plates with features impressed therein via the molding process. The bipolar plates formed by the process have sufficient mechanical strength and bulk conductivity to be used in fuel cells The outer layers provide for enhanced conductivity and resistance to gas permeation.